Efeito radioprotetor do piruvato de etila, sozinho ou como um coadjuvante de amifostina

Entre los radioprotectores con uso clínico se destaca la amifostina (WR- 2721), eficaz pero con efectos secundarios que impiden su uso repetitivo. Es interés de los autores desarrollar radioprotectores menos tóxicos, por sí mismos o como coadyuvantes de amifostina. Ratas machos o hembras se expusieron a una dosis de rayos X de 2 Gy. Se ensayó el piruvato de etilo, solo o conjuntamente con amifostina. Cuarenta y ocho horas después de la exposición a la radiación, se realizó el recuento de eritrocitos, de leucocitos y la fórmula leucocitaria. Los efectos genotóxicos se evaluaron en leucocitos de sangre mediante el ensayo Cometa. Se realizaron también estudios de supervivencia a 60 días post-irradiación. En los animales irradiados disminuyeron los eritrocitos, y el recuento de leucocitos se redujo drásticamente respecto al control, presentando además una fórmula alterada. El tratamiento con piruvato de etilo resultó en una protección de los eritrocitos en ambos sexos. El daño genético disminuyó significativamente por el tratamiento con piruvato de etilo solo o combinado con amifostina, y en hembras se observó una mayor supervivencia solo con el tratamiento combinado. El piruvato de etilo mostró una acción radioprotectora significativa, que podría mejorarse aumentando la dosis o el tiempo de tratamiento, ya que tiene muy baja toxicidad.Among the currently available radioprotectors, only amifostine (WR-2721) has shown in clinical trials to reduce radiation-induced toxicity. This compound is an efficient radioprotector but it exhibits some undesirable side effects which prevent its repetitive use. Efforts are directed to develop radioprotective agents with lower toxicity, with their own protective potential or suitable as coadyuvants of amifostine. The present study describes the results obtained by repetitive oral administration of ethyl pyruvate. Male or female rats were exposed to an X-ray dose of 2 Gy. Forty-eight hours after exposure to radiation, erythrocyte count, leukocyte and differential count were performed. Genotoxic effects were assessed in blood leukocytes by the Comet assay. Survival studies were also performed at 60 days post-irradiation. Eritrocyte and leukocyte were reduced in animals exposed to radiation compared to the control, also presenting an altered formula. Treatment with ethyl pyruvate resulted in a protection on erythrocytes of both sexes. Genetic damage was significantly decreased by ethyl pyruvate alone or combined with amifostine, and in females, higher survival was observed only with combined administration. Ethyl pyruvate showed a significant radioprotective action, which could be improved by increasing the dose or time of treatment because it has low toxicity.Entre os radioprotetores com uso clínico destaca-se a amifostina (WR-2721) eficaz mas com efeitos secundários que impedem seu uso repetitivo. O interesse dos autores é desenvolver radioprotetores menos tóxicos, por si mesmos ou como coadjuvantes de amistofina. Ratos machos ou fêmeas foram expostos a doses de raios X de 2Gy. Ensaiou-se o piruvato de etila, só ou junto com amifostina. Quarenta e oito horas após a exposição à radiação foi realizada a contagem de eritrócitos, de leucócitos e da fórmula leucocitária. Efeitos genotóxicos foram avaliados em leucócitos do sangue pelo Ensaio Cometa. Estudos de sobrevivência foram também realizados a 60 dias pós-irradiação. Nos animais irradiados diminuíram os eritrócitos, e a contagem de leucócitos se reduziu drasticamente em comparação com o controle, apresentando também uma fórmula alterada. O tratamento com piruvato de etila resultou numa proteção dos eritrócitos em ambos os sexos. O dano genético diminuiu significativamente pelo tratamento com piruvato de etila sozinho ou combinado com amifostina, e nas fêmeas se observou maior sobrevivência só com o tratamento combinado. O piruvato de etila mostrou uma ação radioprotetora significativa, que poderia ser melhorada pelo aumento da dose ou do tempo de tratamento, visto que tem baixa toxicidade.Fil: Maciel, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Quintans, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Diaz Gomez, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Formosa Lemoine, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Montalto, Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Lopez, Gabriel Diego. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental; Argentin

Butirato de sódio como agente coadjuvante da ação radioprotetora da amifostina

Entre los escasos radioprotectores en uso, la amifostina resulta eficaz para reducir la toxicidad aguda inducida por la radiación ionizante. Sin embargo, presenta efectos tóxicos importantes que impiden su uso repetido o en dosis altas. Es necesario entonces desarrollar radioprotectores menos tóxicos, por sí mismos o como coadyuvantes de la amifostina en dosis bajas. Se expusieron ratas Sprague-Dawley a una dosis de rayos X de 6 Gy (cuerpo entero). Se ensayó el butirato de sodio como mitigante luego de una dosis baja de amifostina previa a la irradiación. A distintos tiempos después de la irradiación se realizó el recuento de eritrocitos, leucocitos y la fórmula leucocitaria. Los efectos genotóxicos se evaluaron en leucocitos de sangre mediante el ensayo Cometa. Se realizaron también estudios de supervivencia a 60 días y la evaluación histológica del duodeno e intestino grueso. El efecto del tratamiento resultó moderadamente protector respecto de la recuperación de los valores normales de eritrocitos, leucocitos y la fórmula leucocitaria en los animales sobrevivientes en ambos sexos, así como de los epitelios intestinales y el ADN de los leucocitos. También aumentó significativamente la sobrevida a 60 días. La radioprotección con amifostina en una dosis baja seguida de una mitigación con butirato fue claramente significativa.Among the few radioprotectors in use, amifostine is effective in reducing the acute toxicity induced by ionizing radiation. However, it has important toxic effects that prevent its repeated use or in high doses. It is necessary then to develop less toxic radioprotectors, by themselves or as adjuvants of amifostine in low doses. Sprague-Dawley rats were exposed to an X-ray dose of 6 Gy (whole body). Sodium butyrate was tested as a mitigant after a low dose of amifostine prior to irradiation. At different times after the irradiation, the erythrocytes, leukocytes and the leukocyte formula were counted. Genotoxic effects were evaluated in blood leukocytes by the Comet assay. Sixty-day survival studies and histological evaluation of the duodenum and large intestine were also performed. The effect of the treatment was moderately protective with respect to the recovery of the normal values of erythrocytes, leukocytes and the leukocyte formula in the surviving animals in both sexes as well as for the intestinal epithelia and leukocytes DNA. It also significantly increased the 60-day survival. The radioprotection with amifostine in a low dose followed by mitigation with butyrate was clearly significant.Entre os poucos radioprotetores em uso, a amifostina é eficaz na redução da toxicidade aguda induzida pela radiação ionizante. No entanto, tem importantes efeitos tóxicos que impedem seu uso repetido ou em altas doses. É necessário, então, desenvolver radioprotetores menos tóxicos, isoladamente ou como coadjuvantes da amifostina em baixas doses. Ratos Sprague-Dawley foram expostos a uma dose de raios X de 6 Gy (corpo inteiro). O butirato de sódio foi testado como mitigante após uma dose baixa de amifostina antes da irradiação. Em diferentes momentos após a irradiação, os eritrócitos, leucócitos e a fórmula de leucócitos foram contados. Os efeitos genotóxicos foram avaliados em leucócitos de sangue pelo ensaio Cometa. Estudos de sobrevida de 60 dias e avaliação histológica do duodeno e do intestino grosso também foram realizados. O efeito do tratamento resultou moderadamente protetor em relação à recuperação de valores normais de eritrócitos, leucócitos e fórmula leucocitária nos animais sobreviventes em ambos os sexos, bem como protegeu epitélios intestinais e o DNA dos leucócitos. Também aumentou significativamente a sobrevida para 60 dias. A radioproteção com amifostina em baixa dose seguida de uma mitigação com butirato foi claramente significativa.Fil: Costantini, Martin Hernan. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentina. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Diaz Gomez, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Formosa Lemoine, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Montalto, Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: López, Diego Gabriel. Ministerio de Defensa. Instituto de Investigaciones Científicas y Técnicas para la Defensa; ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin

Rat ventral prostate xanthine oxidaseg-mediated metabolism of acetaldehyde to acetyl radical

Alcohol drinking is known to lead to deleterious effects on prostate epithelial cells from humans and experimental animals. The understanding of the mechanisms underlying these effects is relevant to intraprostatic ethanol treatment of benign prostatic hyperplasia and to shed some light into the conflictive results linking alcohol consumption to prostate cancer. In previous studies, we provided evidence about the presence in the rat ventral prostate of cytosolic and microsomal metabolic pathways of ethanol to acetaldehyde and 1-hydroxyethyl radical and about the low levels of alcohol dehydrogenase and aldehyde dehydrogenase. Acetaldehyde accumulation in prostate tissue and oxidative stress promotion were also observed. In this study, we report that in the ventral prostate cytosolic fraction, xanthine oxidoreductase is able to metabolize acetaldehyde to acetyl radical. The identification of the acetyl was performed by GC-MS of the silylated acetyl-PBN adduct. Reference adduct was generated chemically. Formation of acetyl was also observed using pure xanthine oxidase. The generation of acetyl by the prostate cytosol was inhibited by allopurinol, oxypurinol, diphenyleneiodonium chloride, folate, and ellagic acid. Results suggest that metabolism of ethanol to acetaldehyde and to 1-hydroxyethyl and acetyl radicals could be involved in the deleterious effects of alcohol drinking on prostate epithelial cells.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Cytosolic xanthine oxidoreductase mediated bioactivation of ethanol to acetaldehyde and free radicals in rat breast tissue. Its potential role in alcohol-promoted mammary cancer

Epidemiological evidence links alcohol intake with increased risk in breast cancer. Not all the characteristics of the correlation can be explained in terms of changes in hormonal factors. In this work, we explore the possibility that alcohol were activated to acetaldehyde and free radicals in situ by xanthine dehydrogenase (XDh) and xanthine oxidase (XO) and/or aldehyde oxidase (AO). Incubation of cytosolic fraction with xanthine oxidoreductase (XDh+XO) (XOR) cosubstrates (e.g. NAD+, hypoxanthine, xanthine, caffeine, theobromine, theophylline or 1,7-dimethylxanthine) significantly enhanced the biotransformation of ethanol to acetaldehyde. The process was inhibited by allopurinol and not by pyrazole or benzoate or desferrioxamine and was not accompanied by detectable formation of 1HEt. However, hydroxylated aromatic derivatives of PBN were detected, suggesting either that hydroxyl free radicals might be formed or that XOR might catalyze aromatic hydroxylation of PBN. No bioactivation of ethanol to acetaldehyde was detectable when a cosubstrate of AO such as N-methylnicotinamide was included in cytosolic incubation mixtures. Results suggest that bioactivation of ethanol in situ to a carcinogen, such as acetaldehyde, and potentially to free radicals, might be involved in alcohol breast cancer induction. This might be the case, particularly also in cases of a high consumption of purine-rich food (e.g. meat) or beverages or soft drinks containing caffeine.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Delgado, Aurora Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Rat ventral prostate xanthine oxidase bioactivation of ethanol to acetaldehyde and 1-hydroxyethyl free radicals: Analysis of its potential role in heavy alcohol drinking tumor-promoting effects

The ability of the ventral prostate cytosolic fractions to biotransform ethanol to acetaldehyde and 1‐hydroxyethyl (1HEt) radicals was tested. Acetaldehyde formation was determined by GC‐FID analysis in the head space of incubation mixtures. 1HEt was determined by spin trapping with PBN followed by extraction, silylation of the adduct and GC‐MS of the product. Prostate cytosol was able to biotransform ethanol to acetaldehyde in the presence of NADH, hypoxanthine, xanthine, caffeine, theobromine, theophylline, and 1,7‐dimethylxanthine but not in the presence of N‐methylnicotinamide. All these biotransformations were inhibited by allopurinol and were sensitive to heating for 5 min at 100°C. The biotransformation of ethanol to acetaldehyde in the presence of purines as cosubstrates was accompanied by the formation of hydroxyl and 1HEt radicals as detected by GC‐MS, and the process was inhibited by allopurinol. Results suggest that prostate cytosolic xanthine oxidase is able to bioactivate ethanol to acetaldehyde and free radicals. The potential of these processes to be involved in tumor‐promoting effects of heavy alcohol drinking in conjunction with high meat and/or purines consumption is analyzed. Multifactorial epidemiological studies considering that possibility might be convenient.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Delgado, Aurora Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Rat breast microsomal biotransformation of ethanol to acetaldehyde but not to free radicals: Its potential role in the association between alcohol drinking and breast tumor promotion

We recently showed that mammary cytosolic xanthineoxidoreductase had the ability to bioactivate ethanol (EtOH) to acetaldehyde (AC) and free radicals. In thepresent study, we report that the microsomal fraction also biotransforms EtOH to AC. One pathway requires NADPH and the others do not. Both need oxygen. TheNADPH-dependent pathway is not inhibited by CO:O(2) (80:20) or SKF 525A and that excludes the participation of cytochrome P450. It is inhibited bydiethyldithiocarbamate (DDTC), sodium azide, and diphenyleneiodonium (DPI) butnot by desferrioxamine, which suggests a possible role of a non-ironcopper-requiring flavoenzyme. The process was partially inhibited bythiobenzamide (TBA), methylmercaptoimidazole (MMI), and nordihydroguaiaretic acid(NDG) but not by dapsone, aminotriazole, or indomethacin. These results suggestthe potential participation of flavine monooxygenase and of lipooxygenase or ofperoxidases/oxidases having similar characteristics but not of lactoperoxidase orcyclooxygenase. The pathway not requiring NADPH could also be partially inhibitedby DDTC, NDG, azide, DPI, and TBA or MMI but not by the other chemicals. Littleactivity proceeds under nitrogen. Oxidases or peroxidases might be involved. Noformation of 1-hydroxyethyl radicals was detected either in the presence orabsence of NADPH. The nature of the EtOH bioactivating enzymes involved remainsto be established. However, the fact remains that an activation of EtOH to AC wasfound in mammary tissue and could have a significant effect in some stages of theprocess of breast tumor promotion by EtOH.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Delgado de Layño, Aurora M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Rat ventral prostate microsomal biotransformation of ethanol to acetaldehyde and 1-hydroxyethyl radicals: Its potential contribution to prostate tumor promotion

Rat ventral prostate microsomal fraction was able to biotransform ethanol to acetaldehyde and 1-hydroxyethyl radicals (1HEt) in the presence of NADPH and oxygen. The enzymatic processes involved were not inhibited by desferrioxamine, CO, SKF 525A, 4-methylpyrazole, or polyclonal antibody against P450 reductase but they were significantly inhibited by diethyldithiocarbamate, 2-mercapto-1-methylimidazol, thiobenzamide, or diphenyleneiodonium chloride. Results would suggest the partial participation in these ethanol bioactivation processes of flavin containing monooxygenase (FMO) and/or other flavin dependent oxidases/ peroxidases and of a non-iron metal-containing enzymes. Acetaldehyde and free radicals production by prostate microsomal fraction might potentially contribute to tumor promotion in heavy alcohol drinkers.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Delgado De Layño, Aurora, M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Rat liver microsomal and nuclear activation of methanol to hydroxymethyl free radicals

Recent studies from other laboratories reported that during methanol intoxication lipid peroxidation and protein oxidation in liver occurred. Further, they detected free radicals-PBN adducts in bile and urine of methanol poisoned rats. In this work, we report the presence in liver microsomes and nuclei of NADPH dependent processes of hydroxymethyl (HMet) radical formation. The detection of HMet radicals was performed by GC/MS of the trimethylsilyl derivatives of the PBN (N-tert-butyl-a-phenylnitrone)-radical adducts. The formation of HMet radicals was observed only under nitrogen, in these in vitro conditions. Formation of formaldehyde from methanol was observed in aerobic incubation mixtures containing either microsomes or nuclei but also under nitrogen using microsomes. The latter process was not inhibited by diphenyleneiodonium while the anaerobic microsomal one producing HMet was strongly inhibited by it. This shows that they are independent processes. Results suggest that both, liver nuclei and microsomes are able to generate free radicals during NADPH-mediated methanol biotransformation.Fil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Delgado De Layño, Aurora, M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin

Cytochrome P450 reductase-mediated anaerobic biotransformation of ethanol to 1-hydroxyethyl-free radicals and acetaldehyde

The ability of cytochrome P450 reductase to metabolize ethanol (EtOH) to acetaldehyde (AC) and 1-hydroxyethyl free radicals (1HEt) in anaerobic media was studied. Determination of AC was made by GC-FID analysis of the head space of incubation mixtures. The formation of 1HEt was established by GC-MS analysis of the adduct formed between the radical and the spin trap PBN. Results showed that pure human P450 reductase is able to biotransform EtOH to AC and 1HEt in a NADPH-dependent process under an oxygen-free nitrogen atmosphere. Pure FAD in the presence of NADPH was also able to generate AC and 1HEt from the alcohol. Anaerobic incubation mixtures containing either rat liver microsomes or pure nuclei were also able to biotransform EtOH to AC and 1HEt in the presence of NADPH. These processes were inhibited by antibody against rat liver microsomal P450 reductase. Results suggest that semiquinone forms of the flavin in P450 reductase may biotransform EtOH. These reactions might be of some significance in tissues where the P450 reductase is present in the absence of specific forms of cytochrome P450 known to be involved in EtOH metabolism (e.g. CYP2E1). However the toxicological significance of this enzymatic process remains to be established.Fil: Diaz Gomez, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; ArgentinaFil: Delgado de Layo, A. M. A.. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Biochemical and ultrastructural alterations in the rat ventral prostate due to repetitive alcohol drinking

Previous studies showed that cytosolic and microsomal fractions from rat ventral prostate are able to biotransform ethanol to acetaldehyde and 1-hydroxyethyl radicals via xanthine oxidase and a non P450 dependent pathway respectively. Sprague Dawley male rats were fed with a Lieber and De Carli diet containing ethanol for 28 days and compared against adequately pair-fed controls. Prostate microsomal fractions were found to exhibit CYP2E1-mediated hydroxylase activity significantly lower than in the liver and it was induced by repetitive ethanol drinking. Ethanol drinking led to an increased susceptibility of prostatic lipids to oxidation, as detected by t-butylhydroperoxide-promoted chemiluminiscence emission and increased levels of lipid hydroperoxides (xylenol orange method). Ultrastructural alterations in the epithelial cells were observed. They consisted of marked condensation of chromatin around the perinuclear membrane, moderate dilatation of the endoplasmic reticulum and an increased number of epithelial cells undergoing apoptosis. The prostatic alcohol dehydrogenase activity of the stock rats was 4.84 times lower than that in the liver and aldehyde dehydrogenase activity in their microsomal, cytosolic and mitochondrial fractions was either not detectable or significantly less intense than in the liver. A single dose of ethanol led to significant acetaldehyde accumulation in the prostate. The results suggest that acetaldehyde accumulation in prostate tissue might result from both acetaldehyde produced in situ but also because of its low aldehyde dehydrogenase activity and its poor ability to metabolize acetaldehyde arriving via the blood. Acetaldehyde, 1-hydroxyethyl radical and the oxidative stress produced may lead to epithelial cell injury.Fil: Diaz Gomez, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Rodriguez de Castro, C. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Fanelli, Silvia Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Quintans, Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Costantini, Martin Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Jose Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); ArgentinaFil: Castro, Gerardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. GP. CITEFA - Centro de Investigaciones Toxicológicas (I); Argentin